1. Field
The disclosed and claimed concept relates generally to an apparatus that is configured to energize a protective device to open at least a portion of a circuit and, more particularly, to an apparatus that performs a predetermined action when its ability to initiate the opening of the circuit has dropped to a predetermined threshold.
2. Description of the Related Art
Numerous types of circuit interrupters are known. One type of circuit interrupter is in the form of a relay that includes an current measurement circuit that employs various algorithms to determine when to disconnect the power to a large load, such as a motor, in certain predefined overload scenarios. Such circuit interrupters may include an energy storage device such as an electrolytic capacitor to energize a solenoid of a relay which causes another solenoid to change state to cause a contactor to interrupt the circuit. While such circuit interrupters have generally been effective for their intended purposes, such circuit interrupters have not been without limitation.
As is generally understood, the energy storage capability of an electrolytic capacitor can degrade over time, and elevated temperatures can accelerate such degradation. Depending upon the degree of degradation, such a capacitor may store an insufficient amount of energy to energize the solenoid that initiates the opening of the circuit. Moreover, while certain overload conditions can occur in an extremely short period of time, other overload conditions develop over several minutes or even hours, and it is generally undesirable for equipment to suddenly stop operating, whether because the power supply to the equipment has been interrupted or because the equipment has overheated or otherwise failed. It thus would be desirable to address these and other shortcomings known in the relevant art.